Convertible type vehicles unlike sedan and hardtop vehicles do not have any rigid roof for providing strengthening of the vehicle body in cooperation with the vehicle floor pan. As such, the vehicle body floor pan has to be sufficiently strong to carry the forces that are normally carried by the roof of sedan and hardtop type vehicles.
Relatively recent production convertible type vehicles are made with the same vehicle body floor pan as similar sedan and hardtop type vehicles for purposes of economy. The roof of the vehicle is either removed or the vehicle is constructed with a "dummy" roof that can be recirculated through the vehicle body assembly line to provide support between the vehicle windshield header and the rear deck panel of the vehicle during the vehicle body assembly operation. Since the same floor pan is utilized as with sedan and hardtop type vehicles, reinforcement of the floor pan is necessary in order to have the requisite strength for carrying the forces that the roof would otherwise carry.
The David L. Draper U.S. Pat. Nos. 4,457,555; 4,514,891; and 4,570,321 disclose reinforcement of convertible type vehicle body floor pans by a stamped metal center member of an inverted U shape secured to the vehicle body along the central transmission tunnel. A forward section secured to a front end of the center member is attached to the vehicle floor pan at its front end, while a rearward section secured to a rear end of the center member is attached to the vehicle floor pan at its rear end. Between the forward and rearward sections, the center member extends only along the central transmission tunnel of the floor pan and thus does not provide any direct support at lateral extremities of the floor pan adjacent the side door openings of the associated convertible vehicle.